Signaling system



'. w. A. RHODES.

SIGNALING SYSTEM. APPLICATION FILED MAR 22, ms.

Patented Apr. 11, 1922.

- 2 SHEETS-SHEET.

W. A. RHODES.

SIGNALING SYSTEM.

APPLICATION mm MAR 22, 1918.

INVENTOR.

M Rhades ATTORNEYS.

Patented Apr. 11, 1922.

2 SHEETS-SHEET 2.

' such cord circuits superv YVILLIAM A. RHODES. OF EV] YORK, N. Y.,

PATEN AssIeNoR T OFFICE.

T0 AMERICAN TELEPHONE AND TELEGRAPH COMPANY. A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

To all whom it may concern:

lie it known that I, TFLLIJ-JI f1. Rironns, residing at New 'York. in the county oi New fork and State of New York have in vented certain Improvements in Signaling Systems, of which the following is a specification." Y

This invention relates to telephone systems and more particularly to rordcircuits associated therewith.

It is one of the objects oi the invention to providecord circuits which are adapted for making connections "between various types of rural. local and long distance lines. A further object consists in assoriating 'ith cry arranges cuts for informing the OPGI'iliOifV-Jilfl'i a conuec tion has been terminated-by e ther "subs'criber, and in providing means which will insure the operation of such supervise y Sig nals after the subscriber has ceased. in 'ing, Another object consists in; i'cducir equipment for controlling the super-y sory arrangements. Another object consists in providing such cord circuits with improved ringing arrangements whe e )y ringing current of different characte V be s nt out over the various types or" lines connected and whereby ringing current may be transmitted selectively over a' party line. Other and further objects of the invention may be more fully understood lroin the detailed description to be givcz'i later.

WVl1ena connection made with a rural or magneto line with a universal cord circuit the operator notified at the termination of the conneztion by the subscriber transmitting ringing current back over the line and operating a sup isory signal in the cord circuit. In iormer types of universal cord circuits this signal was controlled by a relay havinga double winding. one winding serving to operate the relay when alternating current was s'ent'over the line by the s1ibscribe'r. and the other winding serving to close a locking circui through the supervisory signal so that the supervisory nal would remain in operationa'fteii' the ringing ceased. It has been found in practice that it the subscriber stopped'ringing at that point when the magnetic component in the relay from one winding is equal and opposite to the . am s- Specification of Iietters Patent. Patented Apr. 11 1922 Application filed March 22, 1918; Serial No. 223,995.

when the ringing ceased; In other former types of universal cord circuits this difliculty 1s obviated by using a relay responsive to ringing currentand a second relay for the sole purpose of closing a locking circuit for the supervisorysignal upon the operation of the ringing relay. In the arrangements of the cord circuits of the present invention a ringing responsive relay is provided and the relay which normally serves as a supervisory relay on common battery line connections is also used foi'closing a locking circuit for t hesupervisory signal on a magneto or rural line connection upon the operation of. the ringing relay. This arrangement provides a means for preventing the supervisory signal firoin becoming extinguished afterthe subscriber ceases ringing and also serves to reduce the equipment needed.

In the ringing arrangement associated with a universal cord circuit it has been customary to provide apparatus whereby the operator may ringselectively over either side of the called line either with alternating current when a connect-ion is made with a rural r magneto line, or with superimposed current of either polarity when tL' COI1I1GCt-i01l is made with a common battery or local line, By the above arrangementsfour-party servive may be given on common battery or local lines. In former types of universal cord circuits this ringing arrangement necessitated the use of six different ringing keys. In the arrangements of the present invention the number of ringing keys for accomplishing this purpose is reduced to four, two of the keys being suitable for ringing either overlocal lines or rural lines. This is accomplished by associating with the conductors. which lead from the source of ringing current and normally apply alternating current to these two keys, a relay which operates whenever a connection is made with a local line and switches these conductors to contacts which lead to a source of superimposed current. This arrangement tends to simplify the ringing operation by making it more uniform with the operation and equipment ata position handling connections with common battery lines only.

The invention may now be more fully understood when taken in connection with the accompanying drawing, in the Figures 1 and 52 of which are illustrated the preferred forms of the circuit arrangements of the inapplies ground to one vention. In the Figure l is illustrated a uni-' versal rural cord circuit adapted for making connections between local or common battery lines and rural or magneto lines. In Figure 2 is illustrated a universal toll cord circuit adapted for making connections between local or common battery lines, rural or magneto lines or long distance lines.

In the Figure 1 the lines L and L, illustrate local lines terminating at the switchboard in the jacks J and J respectively. Associated. with the lines L and L are the usual line signal lamps 21 and 24 respectively, together with the customary apparatus associated therewith. The lines L and L illustrate rural or magneto lines terminating at the switchboard in the jacks J and J respectively. Associated with the lines L and L are the usual line signal lamps Q2 and 23 and the customary apparatus associated therewith. The universal rural cord circuit'A is shown terminating in the answering and calling plugs P and P respectively. Associated with the sleeve contact of the plug P .is the relay 1 and the marginal relay 2. When a connection is made with a rural line, such as the line L by inserting the plug 1? in the jack J the relay 1 will operate butthemarginal relay 2 willnot be operated because the winding of the relay associated with the sleeve contactlo'f the ack J is of high resistance. hen a connection is made with a local line. such as the line L by insertingthe plug P in the jack J both of the relays land 2 will. be operated because the winding of the relay associated with the sleeve contact of jack J is of low resistance. Included in the talking conductors of the cord circuit is the repeating coil 20. Included in a bridge associated with the lefthand windings of repeating coil 20 is the relay 3 which responds to alternating cur rent. When a connection with a rural line has been terminated, the subscriber sends ringing current back over the line and .over this bridge. which causes the operation of the relay 3. Under the control of the relay 2-3 is the relay at, which serves upon the energization of relay 3. to close a locking circuit through the signal lamp 25, the operation of which intorms the operator of the termination of the connection. When a connection is made with a local line, the relay 2, as has been formerly pointed out, will. be operated; This opens the bridge associated with the lei tliand windings of repeating coil 20 and side of the line and connects battery to the other side of the line to furnish the talking current for the connection. The winding of the relay 4 is included inthis current supply circuit and when the connection is terminated by the subscriber hanging up his receiver, the relay 4 becomes tie-energized and allows a circuit to be closed through the signal lamp 25.

The operation of the signal lamp 25 serves to inform the operator that the connection has been terminated. Associated with the sleeve of plug P are the relays 5 and 6. When a connection is made with a rural line. such as the line L the relay 5 will be operated but the relay 6 will not be operated, as the winding of the relay associated with the sleeve contact of the jack J 3 is 01": high resistance. lVhen a connection is made with a local line, such as the line L by inserting the plug P in the jack J both of the relays 5 and 6 will be operated, as tie winding oi the relay associated with the sleeve contact of the jack'J isof low resistance. Included in a bridge associated with the righthand windings of repeating coil 20 is the alternating current relay 8. When a connection has been terminated by a subscriber on a rural line ringing current is transmitted back over the line and over this bridge and relay 8 is caused to operate. Under the control of relay 8 is the relay 9, which. upon the ope ation of relay 8, serves to close a locking circuit through the signal lainp 26 and. thereby inform the ope 'ator that the connection has been terminated. hen a connection is made with a local line. the relay 6, as has been'forinerly pointed out, will be energized. The operation of relay 6 opens the bridge associated with the I ithand windings of repeating coil 20 and applies ground to one side of the line and connects battery to the other side of the line to furnish talking current for the connection.

The winding of the relay 9 is'included-in.

this current supply circuit and, accordingly, when the subscriber terminates the connection by hanging up his receiver, the relay 9 will be de-energized and allow a circuit .to be closed through the signal lamp 26, thereby intorming the operator of the termination of the connection. Associated with the talking strands of the cord circuit is the listoning key'K By throwing the listening key K the operator may extinguish either the signal lamp or the signal lamp 26 by opening the circuit closed therethrough.

Associated with the talking strands of the cord circuit are the ringing keys K K K and'K Associated with the ringing keys is a source 01" ringing current, including the generator 85 of alternating current and the batteries 90 and 91. This source of ringing current is so associated with the ringing lccys that superimposed current of a positive polarity is normally applied to keys K and K and alternating current normally applied to the keys K and K Under the control of the relay 6 is the relay 89, which operates whenever a connection is made with a local line. The operation of the relay 89 serves to associate the source of ringing current with the ringing keys IQ and K so that superimposed current of a negative polarity wiil be applied thereto when a connection is made with a local line. The circuit arrangements of the relays associated with the calling end of the cord circuit are slightly different from the arrangements associated with the answering end and illustrate an arrangement desirable for use when a connection is made with an operator at a recording toll board. However, it will be understood that the arrangement illustrated as associated with this answering end of the cord might equally well be employed on the calling end.

The cord circuit B illustrated in the Figure 2, is adapted for making connections between local or common battery lines, rural or magneto lines and long-distance lines, and as the arrangements associated therewith are in many respects similar to those oi the cord circuit A oi Figure 1, similar reference numerals have been used to designate similar objects whenever possible. Associated with the sleeve conductor of the answering plug P, are the relays l and 2, relay 1 operating on connections with magneto lines or long distance lines, and both of the relays 1 and 2 operating when a connection is made with a couunon battery line. These relays perform functions similar to the relays 1 and 2 the cord circuit A.- tallring conductors of the cord circuit B is the repeating coil. 20, which is so arranged that part of it serves as a retardation coil when connections are made involving rural or magneto lines, or long-distance lines. When. a connection is desired involving a common batteryline, it is desirable to employ the coil 20 a repeatingcoil, and there-tore the relay 100, which is controlled by relay 2. is operated and the repeating coil 20 connected such. Associated with the left-hand winding of repeating coil 20 is the relay 3, which responds-to alternating ringing current transmitted over the line when a connection with a magneto line or lon distance line has been terminated. Under the control of the relay 3 is the relay 4, which serves to close a locking circuit through the supervisory signal 25 when a connection has been terminated on a magneto line or long distance line, and which serve, supervisory relay for the signal lamp 25 when a connection is made with a common battery line. Associated with the answering plug P is the relay 5 and the marginal relay the relay 5 operating when a connection is made with a magneto line or long distance line, and both the relays 5 and 6 operating when a connection is made w1th commonbattery line. Associated wlth the right-hand windings of the repeating coil 2O is the relay 8 which responds to alternating ringing current transmitted back over a alled magneto or long distance linewhen a connection between such a line and a com- 'tall ng Associated with the mon battery line has been terminated. Under the control or the relay 8 is a relay 9, which serves to close a locking circuit through the signal lamp 26 when a connection is terminated between a common battery line and a called magneto or long distance line, and which serves a supervisory relay for the signal lamp :26, when a connection is made with a called common battery line. As the right hand winding of the repeating coil 20 is not connected to the cord circuit when a connection is made involving only magneto lines or long distance lines, the termination of such connection at either end of the line is indicated by the lamp 25.

With cord circuits of this type it is commonly the practice to employ a battery for A purposes of a comparatively high voltage and signaling lamps constructed to re cive their normal current at a'lower volt- With the cord circuit B, illustrated in 2, the signal lamps on long distance or magneto connections are lighted from the battery which supplies talking current on common battery connections and since the resistance of the windings of relays 4 and 9, in series with the lamps 25 and 26 respectively, is not sufiicient to reduce the voltage across the lamp terminals by the necessary amount, the resistance units 101 and 102 are also connected in series with the lamps 25 and 26 when they are lighted on long distance or magneto line connections.

The ringing arrangements asso iated with the cord circuit B are slightly ditierent from those of the cord circuit A. Included in the talking strands oi the cord circuit B are the ringing keys K and K Associated with these keys are the master keys K, and K Associated with the keys K and K is a source of ringing current, including a generator and the batteries and 5)]. Alternating ringing current is normally applied i'rom the generator 85 t0 the keys K and IQ, hen a connection is made with a common battery line and it is desired to use superimposed current of either polarity for ringing purposes, relay 89 will operate and connect the conductors leading "from keys K and K, to conductors leading to the con tacts of keys IQ and K to which kegs the source of ringing current supplies superhuposed current of either polarity.

By the above arrangements alternating" ringing current may be transmitted selectively over a called magneto or long distance line by operating either the key K or the key K By operating different combinations oi the keys K and K together with the k l: and K, superimposed current of either polarity may be transmitted selectively over a called common battery line.

The operation of cord circuit A upon a connection between two magneto lines is as i ollowsz-lvhen a subscriber on a magneto llzl - contacts of plug P jack J conductor 3b,

the line L desires a connection )iiice he will transmit ring- -urrent o the sides the line L and ti rough the winding of relay This will energize the relay 1'! and close the following circuit: from ground, winding of relay l3, conductor 27. armature and contact of relay l2, conductor 28,. armature and'contact of relay is to bantery and ground. The closing of this circuit will energize relaj which closes the following circuit: from groundand battery. contact and armature of relay let. conductor 28, contact and armature of relay 12 condiiictor 2T lefthand contact and arnniture relay l3, conductor 29 ri" ithand armature and contact of relay 13, over c niductor Ell, filament of signal lamp 2. to ground. At the same time a locking circuit will be closed through the signal lamp 522 over conductors 32 and 29 so that the signal lamp ill not be extinguished when the subscriber on line L ceases to ring. Upon the operation of signal lamp 22 the. operator will insert the plug P of cord circui ii into the jack 5 This will close the following circuit: from ground and battery 33. winding of marginal relay "2, conductor 34L, winding of relay l, conductor 35,

winding ofrelay 1.4 to ground. The closing of the above described circuit will energize relay 14 which will pull up its arn'iature and open the circuit closed through the line signal lamp 22. The closing of the above mentioned circuit will energize relay 1, but, asthe winding of relay is of high sist-ance it will not energize the marginal relay 2. After the operator has conne ted the cord circuit to the line. li by inserting the plug P in the jack l the listening key K is thrown and the operator may ascertain with whom the connection is desired. If a connection is desired with another magneto line such as the line L the operator inserts the plug P into the jack J W hen the plug P is inserted in the jack J the following circuit is closed: from ground and battery 64, conductor 65, armature and contact of marginal relay 6, conductor 66, upper winding of marginal relay (3, conduc tor 67, winding of relay 5 conductor 68, sleeve contacts of plug P and acl: J conductor 69, winding of relay -19 to ground. The closing of the above described circuit will operate the relay 5 but, as the. winding of relay 19 is of high resistance, it will not operate the marginal relay 6. The operation of the relay 5 by pulling up its upper armature completes the talking circuit of the cord circuit and by pulling iip'its lower armature places the signal lamp 26 under the control of relay 9. The operator may now transmit ringing current to the subscriber selectively over either side of line L by operating either thekey K or the key K ringing circuit is completed by applying ground to the other contact of key K if it is desired to transmit ringing current over the other side of the line L the key K 1 operated and ground is applied to the ti conductor of the cord circuit. Alternatin ringing current will then be applied to the ring conductor of the cord circuit as follows: from ground, generator 85, conductor contact and armature of relay 89. conductor 87, contact of key K and over the ring COi1- ductoiof the cord circuit.

WVhen the connection is terminated either the subscriber on the line L or on the line or both will transmit ring-inecurrent over the line and through apparatus associated with the universal cord circuit A in the following manner :When the subscriber on theline L transmits ringing current over the line for the purpose of notifying the operator that the connection has been completed, the ringing current will be transmitted over the talking strands of the cord circuit and through the left hand windings of the repeating coil 20. From this point ringing current will be transmitted over the following circuit; from upper left hand winding of repeating coil 20, over conductor 37, contact and armature of relay 2, conductor 38, winding of. relay 3, conductors 39 and t0 to. the lower left hand winding of re peating coil 20. This will energize the relay 3 which will pull up its armature and close the following circuit: from ground. contact of listening key K over conductors 42 and 4:8, filament of signal lamp 255, over conductor 44:, contact and armature of relay 1, over conductorsdo and et6, contactand armature ofrelay 3, conductors 4LT and 48, contact and armature of relay 2, conductor 49, winding of relay 4, to battery and ground. The closing of this circuit will light the signal lamp 25 and inform the operator that the call has been completed, The closing of this circuit will also energize the relay 4 which will be locked up over the following circuit: from conductdr 45., over conductorSO, contact and armature of relay 4, over conductors 51. and 48, contact and armature of relay- 2, over conductor 49, winding of relay 4, to battery and ground. Upon the operation of the signal lamp 25 the operator either by disconnecting the hord circuit from the lines L and L or by throwing the listeningkey K may open the circuit formerly closed through the signal lamp 25 and allow it to be extinguished. Should the subscriber on the line L desire to inform the operator that the connection had terminated, ringing current would be transmitted by the subscriber over the line L and over the talking strands of the cord circuit to the right hand windings of repeating coil 20. From this point the ringing current will be transmitted over the following circuit; from the upper right hand winding of repeating coil 20, over conductor 52, armature and contact of relay 6, conductor 53, winding of relay 8, over conductor to the lower right hand winding of repeat ing coil 20. This will energize the relay 8 which will pull up its armature and close the following circuit: from ground, contact of listening key K conductors l2 and 56, filament of signal lamp 26, armature and contact of relay 5, conductors 57 and 58, armature and contact of relay 8, conductors 59 and 60, armature and contact of relay 6, conductor 61, winding of relay 9, to battery and ground. The closing of this circuit will operate the signal lamp 26 and inform the operator that the connection has terminated. The closing of this circuit will also energize the relay 9 which will pull up its armature and become locked up as follows: from conductor 57, over conductor 62, armature and contact of relay 9, conductors 63 and 60, contact and armature of relay 6, conductor 61,. winding of relay 9 to battery and ground. When the operator has been thus informed that the connection has terminated, she may extinguish the signal lamp 26 by throwing the listening key K and opening the circuit closed therethrough or by disi-onnecting from line L,, thereby releasing relay 5 and thus opening the. circuit through lamp 26.

The operation of the cord circuit A upon a connection between two common battery lines or between a common battery line and a magneto line is as follows :-When a subscriber on one of the common battery lines, such as the line L,, removes the receiver from the hook, the following circuit will be closed: fromground, conductor 71, battery 70, righthand winding of relay 10, over one side of transmission line L and through the subscribers telephone set, over the other side of the transmission line L,, through the lefthand winding of relay 10, over conductor 173 to ground. The closing of this circuit will energize the relay 10, which will pull up its armature and close the following circuit: from ground, conductor 71, battery '70, armature and contact of relay 10. conductor 72, filament of signal lamp 21 to ground. The closing of this circuit will operate the signal lamp 21. Upon the operation of the signal lamp 21, the operator will insert the plug P of the cord circuit into the jack J, and the following circuit will be closed: from ground, battery 33,

winding of marginal relay 2, conductor 34, winding of relay 1, conductor 35, sleeve contacts or' plug 1 and jack J conductor 73, winding of relay 11 to ground. The closing of this circuit will energize the relay 11, which will pull up its armature and open the circuit formerly closed about the windings of relay 10, which will in turn release its armature and extinguish the signal lamp 21. As the resistance of the winding of the relay 11 is small, the closing of the above described circuit will energize both of the relays 1 and 2. The operation of marginal relay 2 applies ground to its upper armature and conductor 37 and to the upper lefthand winding of repeating coil 20. The enei'gization of marginal relay 2 also applies battery to the lower lefthand wipding of repeating coil 20 as follows: from round and battery, winding of relay 4-, conductor 49, armature and contact of relay 2, conductors 7i and 40, to lower lefthand winding of repeating coil 20. The above described arrangements provide a means for supplying the talking current when a connection is made with a cominon battery line. The operator now throws the listening key K and ascertains with whom a connection is desired. If a connection is desired with a magneto line, such as the line L,,, the operator inserts the plug P into the jack J \Vhen the plug P is inserted in the jack J, the operation is substantially the same as has been already described, and a further description will be omitted. If the operator ascertains that a connectlon is desired with another common battery line, such as the line L,, the plug P is inserted in the jack J, and the following circuit is closed; ground and battery (34, conductor 65, armature and contact of marginal relay (5, conductor 66, upper winding of marginal relay 6. conductor 67, winding oi relay 5, conductor (38, sleeve contacts of plug P and jack J conductor 75. winding of relay 16 to ground. As the resistance of the winding of relay 16 is small, the closing of the above described circuit will energize both the relay 5' and the marinal relay 6. The energization of the relay 5 causes it to pull up its upper armature and complete the talking circuit of the cord circuit, and by pulling up its lower armature places the signal lamp 26 underthe control of relay 9. The energization of marginal relay 6 causes it to pull up its armature and the circuit formerly completed about the winding of inarginal relay 6 is now completed as follows: from upper winding of marginal relay 6 to connecting point 76, thence through the lower winding of relay 6, over conductor 77, winding of relay 7, to battery and ground. The energization of marginal relay 6 applies ground to conductor 52 and to the upper righthand winding of repeating coil 20 and connects to the lower righthand winding of broken. As

repeating coil 20 a battery to supply the talking current as follows: from ground and battery, winding of relay 9, conductor 6i, armature and contact of relay 6, conductors 78 and 55, to the lower righthand Winding of repeating coil 20.

When a connection has been made with a common battery line the operation of relay 6 also closes the following circuit: from ground and battery 84, armature and contact of relay 6, conductor 88, winding of relay 89, to ground. Upon the operation of relay 89 the operator may now transmit superimposed ringing current out over the line L, selectively by operating one of the ringing keys K,, K K, and K as follows: if it is desired to send superimposed positive current out over the tip conductor of the cord circuit, the key K is thrown. This applies ground to the ring conductor of the cord circuit, and applies superimposed positive current to the tip conductor of the cord circuit as follows: from ground and generator 85, battery 91, conductors 92 and 93, contact of key K, and over the tip conductor of the cord circuit. If it'is desired to send superimposed positive current out over the ring conductor of the cord circuit the key K is operated. This applies ground to the tip conductor of the cord circuit and applies superimposed positive current to the ring conductor as follows: from ground and generator 85, battery 91, conductors 92 and 94, contact of key K, and out over the ring conductor of the cord circuit. If it is desired to send superimposed negative current out over the tip conductor of the cord circuit the key K, is operated. This applies ground to the ring conductor of the cord circuit and applies superimposed negative current to the tip conductor of the cord circuit as follows: from ground and generator 85, battery 90, contact and armature of relay 89, conductors 87 and 88, contact of key K, and over the tip conductor of the cord circuit. If it is desired to send superimposed negative current over the ring conductor of the cord circuit, the key K is operated. This applies ground so the tip conductor of the cord circuit andapplies superimposed negative current to the ring conductor as follows: from ground, generator 85, battery 90, contact and armature of relay 89', conductor 87, contact of key K, and over the ring conductor of the cord circuit.

When the subscriber on the line L, terminates theconnection by hanging up the receiver, the current supply circuit will be has been formerly pointed out, the winding of the relay 4: was included in the current supply circuit. Accordingly,

this relay will be tie-energized when the talking circuit is broken and, by allowing its armature to retract, will close the following circuit: from ground and. battery 33, over conductor 79, contact and armature of relay 2, conductor 80, contact and armature of relay 4, conductors 50 and 45, armature and contact of relay l, conductor 4.4, filament of signal lamp 25, conductors a3 and 42, contact of listening key K, to ground. The closing of this circuit will operate the signal lamp 2:) and inform the operator that the connection has been terminated by the subscriber on the line L,. The operator may then throw the listening key K, or disconnect and thereby extinguish the signal lamp 2:) by opening the circuit closed therethrrmgh. W hen the subscriber on the line L, hangs up the receiver, the current supply circuit will be broken. As has been for merly pointedout, the winding of relay 9 is included inthis current supply circuit. Accordingly, when the current supply circuit is brokenby the subscriber on line L the relay 9 will be tie-energized and the following circuit will be closed; from ground and hatteryb l, armature and contact of relay #3, conductors 83 and F42, armature and contact of relay 7, conductor Slhcontact and armature of relay 9, conductors 62 and 57, contact and armature of relay 5, filament of signal lamp 26, conductors 56 and 42, contact of listening key K, to ground. The closing of the above described circuit will light the signal lamp 226 and inform the operator that the connection has been terminated by the subscriber on line L the signal lamp 26 by operating the listening key K, and opening the circuit closed therethrough or by disconnecting.

The cord circuit A may also be employed for making connections involving a common battery line and a. magneto line, such as a connection between the lines L, and L or between the lines L, and L As the operation of the supervisory and ringing arrangements associated with the cord circuit in such a connection will be the same as formerly described separately no further de scrintion thereof will be given.

The operation of the universal toll cord circuit l: is as follows: when a connection is made with the cord cireuit'Bbctween two magneto lines or two long-distance lines, the relays'l and 5 will be operated. but the mar ginal relays 2 and 6 will not beoperated, as the sleeve circuits associated with the jacks oflincs of this type are of high resistance. W hen a connection between two lines of this type is terminated, the subscriber or the distant opei or will transmit alternating ringing current back over the lines and over the talking strands of the cord circuit. This alternating ringing current will be trans mitted through the lefthand windings of the repcating coil 20 and over conductors 105 The operator may extinguish and 106 and through the winding of relayfS.

'As the relay 3 is responsive to alternating current. it will be operated, and. together with the aforementioned operation of relay 1, will close the following circ'uit:from ground, armature and contact of relay 1. conductors 107 and 108, contacts of key K conductor 109, filament of signal lamp 25, conductors 110 and 111, armature and contact of relay 3, conductor 112, resistance 101. contact and armature of relay 2, conductor 113. winding of relay 4 to battery and ground. The closing of the above described circuit lights the signal lamp 25 and energizes the relay 4, which pulls up its armature and closes the following locking circuit: from conductor 111, over conductor 114. armature and contact of relay. resistance 101. contact and armature of relay 2, conductor 113, winding of relay f to battery and ground. The operation of the signal lamp 25 will inform the operator that the connection is terminated. The operator may extinguish the signal lamp 25 by throwing the listening key K and opening the circuit closed therethrough or by disconnecting and thereby removing ground from the locking circuit at relays 1 and 5.

When a connection is made with the cord circuit B between two common battery lines, both of the relays 1 and 2 and the relays 5 and 6 will be operated, as the sleeve circuits associated with the jacks of such lines are of small resistance. The operation of the relay 2 serves to open the bridge, including conductors 105 and 106, which is associated with the lefthand winding of repeating coil 20. and applies ground to the conductor 105 and to the other side of the talking circuit a source of current supply as follows: from ground and battery, winding of relay 1, conductor 113, armature and contact of relay 2, conductor 115. conductor 106 and lowcz lefthandwinding of repeating coil 20. This last mentioned circuit includes the winding of the relay 4;. which becomes energized until the connection with the common battery line is terminated and the circuit is broken by the subscriber hanging up his receiver. Vheu the circuit is broken. the relay 4. will be deen-ergized and the followingcircuit will be closed: from ground and battery. conductor 1.16. contact and armature of relay 2, conductors 117 and 118, contact and armature of relay 4. conductors 114C, and 110, filament of signal lamp 25. conductor 109. contacts of key K. conductors 108 and 10?. contact and armature of relay 1 to ground. The closing of this last mentioned circuit operates the signal lamp 25 and informs the operator that the connection has been terminated. lVhln a connection between two common battery lines is made, it is desirable to employ coil 20 as a repeating coil. Accordingly, when the marginal relay 2 is op erated. the following circuit is closed: from ground and battery, conductor 116, contact and armature of relay 2, conductors 117 and 110. lower winding of relay 100, conductors 120. 121 and 107, and contact and armature of relay 1. to ground. The closing of this circuit energizes relay 100. which pulls up its armature; opens a connection between conductors 103 and l kl and the talking strands of the cord circuit; and connects the conductors leading from the righthand winding of repeating coil 20 to the talking strands. and thus connects coil 20 as a repeating coil in the talking circuit. hen the calling plug P. is inserted in a common battery line. the relay 5 and the relay 6 operate. as has been formerly pointed out, and serve to applv ground to the conductor 1.22 and thence to one of the talking strands of the cord circuit.

source of currentsupply is connected to the other of the talking strands of the cord circuit as follows: from ground and battery, winding of relay 9, conductor 124i, armature and contact of relay 6, conductor 123. lower righthand winding of repeating coil 20, and thence over the talking strand of the cord circuit. The winding of the relay 5) is included in this current supply circuit. and when the circuit is broken by the subscriber hanging up his receiver and terminating the connection, the relay 9 will be tie-energized and the following circuit will be closed: from ground and battery, conductor 125, contact and armature of relay 6, conductors 126 and 127, contact and armature of relay 0,

conductor 128, filament of signal lamp 26,

conductor 129, contact of key K conductors 108 and 121, contact and armature of relay 5 to ground. The closing of this circuit will operate the signal lamp 26 and inform the operator that the subscriber has terminated the connection.

If the connection is one involving a common battery line on the calling end of the cord and a magneto or long distance line on -the answering end, it is found desirable to employ the repeating coil 20. Upon such a connection when the plug P is inserted in a common battery line, the relays 5 and 6 will be operated as has been previously pointed out. The operation of the relays 5 and 6 will close the following circuit; from ground and battery, conductor 125. contact and armature of relay 6, conductors 126 and 130 upper winding of relay 100, conductors 120 and 121, contact and armature of relay 5, to ground. The closing of this circuit will energize the relay 100 which will in a manner previously pointed out include the coil 20 asa repeating coil in the talking circuit of the cord. The supervisory arrangements associated with cit-her side of the cord circuit upon such a connection will function in the same manner as previously described and a further description of the operation may be omitted.

If a connection is one involving a magneto complished by operating either the key or long distance line on the calling end of the cord and a common battery line on the answering end, the repeating coil 20 will be cut into service by the apparatus associated with the answering end of the cord as previously pointed out. 11 the subscriber on the magneto line or the distantoperator on the long distance line in such a connection desires to inform the operator that the connection has been terminated, alternating ringing current will be transmitted back over the line and through the right hand windings of the repeating coil 20 and thence over conductors 122 and 123 and the winding of relay 8. The relay 8 responds to alternating current and is energized. The operation of relay 8 serves to close a circuit through the relay 9 and the signal lamp 26 in a manner similar to the operation of the relays 3 and 4E and accordingly a further description of the operation will be omitted.

The operation of the ringing arrange ments associated with the cord circuit B is as follows: when a connection is made with the cord circuit B and amagneto line or a long distance line it is desirable to ring selectively over either side of the line with alternating current. This may be accomplished by operating either the key K, or the key K When the key K is operated ground is applied to the tip conductor of the cord and one side of the line. Alternating current is applied to the ring conductor of the cord and the other side of the line as follows: from ground and generator 85, conductor 134i, contact and armature of relay 89, over conductor 141, contact of key K and over the ring conductor of the cord circuit. When the key K is operated ground is applied to the ring conductor of the cord circuit and one side of the line as follows: from ground, contact of key K conductor 137Qcontact of key K and ring conductor of the cord. Alternating current is applied to thetip conductor of the cord and the other side of the line as follows: from ground and generator 85. conductor 1.34, contact and armature of relay 89, over conductors 1 11 and 136, contact of key K thence over the tipconductor of the cord and the other side of the line.

Vwien a connection is made with the cord circuit'B and a common battery line, it is desirable to ring selectively'over-either side of the line with superimposed current of either polarity, where such lines are provided for four-party service. This is E- or the 'key K together with the key 'or the key K When a connection is made with a common battery line and the calling plug P, is inserted in the jack of such a line, the relays 5 and 6 will be operated, as has been previously pointed out. w The operation of the relay 6 closes the following circuit:

to the ring conductor of the cord as follows:

from ground generator 85. battery 90, conductor 135, contacts of key K and key K, conductor 133, contact and armature of relay 89, conductor 1 11 contact of. key K and over the ring conductor of the (50rd. By operating the key K ground may be applied to the ring conductor of the cord as follows: "from ground and contact of key K conductor 137 and contact key K Superimposed current of a negative polarity may be applied to the tip conductor of the cord as fol lows: from ground and generator'35, battery 90, conductor 135, contacts of key K and K conductor 133, contact and armature of relay 89, conductors 1 11 and 136, contact of key K and over the tip conductor of the cord. By operating the key K and the key K ground will be applied to the ring conductor of the cord follows: from ground and contact of key K over conductor 137 and contact of key IQ. Superimposed current ota positive polarity will be applied to the tip conductor f the cord as follows: from ground and generator 85. battery 91 conductors l4c0and 138, contacts of key K and key K conductor 133, contact and armature ot relay 89,-c011duct01s 1 11 and 136, contact of key K and over the tip conductor of the cord. By operating the keys K and K ground will be applied to the tip conductor of the cord as -follows: from ground, contact of key K conductor 1333, contact and armature of relay S9, conductors 141 and 136, contact o key K to tip of cord.

Superimposed current of positive polarity will be applied to the ring conductor of the cord as follows: from ground and generator 85, battery 91. conductors 1 10 and 139, contacts of-key K, conductor 1337, contact of key K and over the ring conductor of the cord. V

While this invention has been disclosed as embodied in certain specific arrangements which have been deemed desirable, it will be understood that it iscapable of embodiment -in many and widely varied forms without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

'1. In a telephone system, a cord circuit adapted to interconnect'common battery lines, magneto lines or long distance lines,

a supervisory signal, a relay exercising direct control over said signal when a connection is made with a common battery line, and a relay responsive to alternating cur rent and closing a circuit through said signal when a connection is made with a magneto or long distance line, said first mentioned common battery relay serving as a lock up relay for said circuit.

2. In a telephone system, a cord circuit adapted to interconnect lines of diiferent types, a relay responsive to ringing current associated with said cord circuit, a supervisory lamp, a supervisory relay, and means whereby when said cord circuit is associated with one type of line and ringing current is transmitted over said line said first mentioned relay'is actuated to close a circuit for said supervisory lamp and supervisory relay, said supervisory relay then closing a locking circuit for said lamp.

3. In a telephone system, a cord circuit adapted to interconnect lines of different types, a relay responsive to ringing current associated with said cord circuit, a supervisory lamp, a supervisory relay, means whereby when said cord circuit is associated with one type of line and ringing current is transmitted over said line said first mentioned relay is actuated to close a circuit for said supervisory lamp, and a locking circuit for said supervisory lamp including 9 said supervisory relay.

4. In a telephone system, a cord circuitadapted to interconnect lines of different types, a relay responsive to ringing current associated with said cord circuit, a supervisory lamp, a supervisory relay, means whereby when said cord circuit is associated with one type of line and ringing current is transmitted over said line said first mentioned relay is actuated to close a circuit for said supervisory lamp and supervisory relay, said supervisory relay then closing a locking circuit for said lamp, and means whereby when said cord circuit is associated with a line of another type, said first mentioned relay is disconnected from the cord circuit and a source of battery supply current is connected thereto through said supervisory relay, said supervisory relay when so related to the cord circuit exercising direct control over the supervisory lamp.

including four ringing keys, a, source of current, means operating when the cord circuit is associated with a line of one type for applying alternating current from said source to all of said keys and for superimposing direct current on the alternating current applied to two or said keys, and means operating when said cord circuit is connected with another type of line for superimposing direct current on the alternating current applied to all of'said keys.

7. In a telephone system, a cord circuit including four ringing keys, a source of current, means operating when the cord circuit is associated with a line of one type for applying alternating current from said source to two of said keys and to one side of'the line and to the other two keys and the other side of the line and for superimposing direct current of one polarity on the alternating current applied to one of said first mentioned two keys and for superimposing direct current of an opposite polarity on the alternating currentapplied to one of said second mentioned two keys, and means operating when the cord circuit is connected with another type of line for superimposing direct currents of opposite polarity on the alternating current applied to said remaining two keys.

8. In a telephone system, a cord circuit, a plurality of keys, a source supplying currents of different characteristics means normally applying current of one character from said source to said keys, and means operating automatically when said cord circuit is connected to a certain type of line to apply current of a different character from said source'to said keys.

In testimony whereof I have signed my name to this specification this 18th day of March, 1918. 

